The present invention relates to the shock absorber using bellows.
This type of bellows type shock absorber is adapted to absorb vibration by virtue of the spring characteristics of the bellows which is made of a resilient material and interpositioned between the source of vibration or shock and an item requiring a shock absorbing protection. Such shock absorber is employed in various types of shock absorbing equipment since its resonance point can be varied as required by varying the number of crests, diameter and wall thickness of the bellows.
The performance generally required for the shock absorber is important in two points that the resonance frequency is low and the magnification ratio of resonance is small.
Rubber-based shock absorbers of various types of conventional shock absorbers are disadvantageous in that the resonance frequency used by them is high but, for the spring type and air-cushion type shock absorbers, the resonance frequency can be shifted to the lower frequency zone.
However, it is difficult to reduce the magnification of resonance in the case of these shock absorbers since repercussive resilience acts on application of vibration, and this is the same with the bellows type shock absorber in the theoretically similar construction to the spring type shock absorber.
How to reduce the magnification of resonance at this resonance point is the greatest problem relating to this bellows type shock absorber.
An object of the present invention is to provide a bellows type shock absorber capable of reducing the magnification of resonance at the resonance point.
This object is achieved by providing the shock absorbing column made of a gelled material in the bellows.
Another object of the present invention is to provide a sealed bellows type shock absorber which can be used even under adverse environmental conditions and can be achieved by providing a sub-bellows in addition to the main bellows.
Another object of the present invention is to provide a bellows type shock absorber for which the resonance frequency in the shock absorber of the present invention can be varied in accordance with variation of the load applied to the main bellows, and this object can be achieved by providing the flow control means for the through hole for use in suction and discharge of air by the bellows.